Subaru’s basic 2-liter EJ20 opposition engine appeared under the hoods of cars in 1989. It debuted on the Legacy and was the successor to the old 1.8-liter engine, bearing the designation EA82. For many years, literally until 2010, the EJ20 engine became the main powertrain for most Subaru models.
In addition to the 2-liter engine, the EJ family includes power units with a working volume from 1.5 to 2.5 liters. They have corresponding designations: EJ15, EJ16, EJ18, EJ22 and EJ25. Since 2012, these engines gave way to new units. In particular, a new atmospheric FB20 and turbocharged FA20 were launched.
Technical specifications
| Characteristics | European modifications | Japanese modifications |
|---|---|---|
| Determined displacement | 1994 cm³ | 1994 cm³ |
| Power system | injector | injector |
| Engine power | 115 hp | 125 – 155 hp |
| Torque | 165 Nm | 175 – 195 Nm |
| Cylinder block | aluminum H4 | aluminum H4 |
| Cylinder head | aluminum 16v | aluminum 16v |
| Cylinder diameter | 92 mm | 92 mm |
| Piston stroke | 75 mm | 75 mm |
| Compression ratio | 9.5 | 10 |
| Engine features | SOHC | SOHC |
| Hydrocompensators | before 1994 | before 1994 |
| Transmission timing | belt | belt |
| Fasor regulator | no | no |
| Turbocharger | no | no |
| What oil to pour | 4.0 liter 5W-30 | 4.0 liter 5W-30 |
| Fuel type | AI-92 | AI-95 |
| Ecological class | EURO 2/3 | EURO 2/3/4 |
| Example service life | 300,000 km | 275,000 km |
| Engine weight | 130 kg | 130 kg |
The design of the Subaru EJ20 engine and its versions
The Subaru EJ20 gasoline engine was designed by engineers of Fuji Heavy Industries, which owns the car manufacturer. The engine is opposed with an aluminum block, cast iron liners. Cylinder diameter is 92 mm and piston stroke is 75 mm. The working volume is 1994 cc.
Each of the connecting rods is connected to the crankshaft with its own neck – as on a 4-cylinder engine. However, the neighboring pistons 1 and 2, 3 and 4 on the Opposite do not move in provo-phase, but always occupy the same position: synchronously occupy the top or bottom dead points. Accordingly, the first and second pair of pistons of a 4-cylinder opposition engine move in anti-phase.
Subaru EJ20 engine block heads are aluminum. Adjustment of thermal clearances of valves is made by selection of washers. In the first modifications of the engine, bearing the index EJ20E in the cylinder head is installed one camshaft. The same engine with two (DOHC) camshafts in the heads is designated EJ20D.
The timing drive uses a toothed belt, which must be changed every 100,000 km.
In 1994, Japanese engineers revised the design of the 2-liter engine: its block switched to an open cooling jacket. Thanks to this technological solution, the engine became much lighter. The crankshaft supports were also changed: instead of three supports, the crankshaft was “stacked” on five supports.
The first turbo engine of the EJ family was EJ20G, which developed from 200 to 240 hp under the hood of such models as Legacy RS, Legacy GT and Impreza WRX. In 1996, it was replaced by the EJ20K (280 hp) turbo engine with an “open” block.
In 1999, a major modernization took place. The block design was again interfered with: this time the thrust rings were moved from the third support to the last – the fifth. The block heads were revised to include swirl intake ducts. All engines of Subaru EJ series of the second generation are designated by an index of three digits: EJ201, EJ202 and so on. The first three variants of the updated 2-liter opposition engines were equipped with single-shaft heads.
In 2003, Subaru debuted the EJ202 engine, whose cylinder head and block were further lightened, the liners became thinner, and the length of the exhaust manifold paths became the same for all cylinders (the so-called “spider” – exhaust manifold 4-2-1). The EJ203 engine differs from it by an electronic throttle and the presence of a mass fuel consumption sensor.
With the engine EJ204 2-liter opposition engines Subaru again got the cylinder head with two camshafts. At the same time on the intake camshafts appeared phase shifters. Maintenance of such an engine is extremely difficult: replacement of plugs, replacement of the timing belt
According to the designation of Subaru engines, it is impossible to determine whether it is turbocharged or atmospheric. Turbines were equipped with units under the index EJ205 (Impreza WRX, Forester) and EJ207 (WRX STI for the Japanese market). Since 2001, this engine was equipped with all modifications of Impreza WRX for all markets. Note that the mentioned engines were equipped with a single turbocharger. Since 2003, the EJ207 engine was equipped with one Twin Scroll turbine.
Biturbo engines among two-liter engines are EJ206 and EJ208, which from 1998 to 2003 were installed on Legacy GT/GT-B for the Japanese market.
Typical problems and weaknesses of the EJ20 engine
With its rather storied history, Subaru’s 2-liter EJ20 opposition engine has a rather controversial reputation. Some people have this engine runs more than 400,000 kilometers, while others have it constantly breaking down and being a source of high costs.
We can safely say that the most survivable are atmospheric versions, such as EJ20, EJ201 and EJ202 – relatively simple, with a single camshaft in the cylinder head, designed for 92 gasoline. Nevertheless, these engines are demanding to fuel quality and oil quality, which should be changed every 7500 km – so experience shows. If to adhere to longer service intervals, the EJ series atmospherics will “answer” by oil rings seizure and accompanying increased oil consumption. Besides, the horizontal location of cylinders is a prerequisite for increased oil consumption, which is not able to independently flow down the cylinder walls.
At the same time, Japanese engines of EJ20 family quite willingly pass oil through the valve cover gaskets and through the crankshaft oil seal. And when the crankcase ventilation system is clogged, the oppositional motor very quickly starts to squeeze out the oil seals.
A known design disadvantage of these engines is poor cooling of the 4th cylinder: the piston heats up, expands and begins to “scuff” its skirts and cylinder walls. because of its overheating there is an ellipse of the cylinder. The piston starts knocking first on a cold engine and then on a warmed up engine.
All the journals of the compact crankshaft of the opposition 4-cylinder engine are very narrow, hence the load on them is high. The risk of rapid wear is very high if the engine temperature is not maintained and poor quality oil is used.
In turbocharged engines of the EJ series all these failures occur early, literally at a mileage of 100,000 km. In addition, turbine malfunctions are observed.
When using poor quality gasoline, gasoline with low octane number, turbo engines Subaru very quickly suffer from detonation. The load on the block and connecting rod liners increases excessively. They are literally welded to the crankshaft, which at the same moment leads to the breakage of the connecting rod. Usually the connecting rods of “hot” 3rd and 4th cylinders break.